Electric heater



Patented Mar. 2|, |899.

E. E. GOLD. ELECTRIC HEATER.

(Application filed Jan. 8, 189B.)

(No Model.)

m m m m l I l l l I n l .n

m: News PETERS co, FHoToLlwo., wAsHlNswm, u. u

No. 62|,604. Patented Mar. 2|, |899.

' E. E. GOLD.

ELECTRIC HEATER.

(Application Bled Jan. 8, 1898.) (No Model.)

2 Sheets-Sheet 2.

WITNESSES: INVENTOR:

n MJ m. By his farneys.

m: mums crans 00,. Pnuouma. wAsHmnToN. n, c

UNITED STATES PATENT OEEicE.

EDVARD E. GOLD, OF NEW YORK, N. Y.

ELECTRIC HEATER.

SPECIFICATION forming part of Letters Patent No; 621,604, dated March21, 1899. Application filed January 8, 1898. Serial No. 666,024. (Nomodel.)

To @ZZ whom t may concern.-

Be it known that I, EDWARD E. GOLD, a citizen of the United States,residing in the city, county, and State of New York, have inventedcertain new and useful Improvements in Electric Heaters, of which thefollowing is a specilication.

This invention provides an improved construction of electric heaters ofthat class wherein the heat is generated by passing an electric currentthrough a coil or helix of resistant-wire which is exposed to the air orother fluid, by the circulation of which the generated heat is conductedaway.

My present invention relates chieliy to the means for supporting a helixof resistant-wire, and particularly when such helix is wound or coiledhelically.

My invention provides also other features of construction pertaining toelectric heaters.

In the accompanying drawings, Figure l is a fragmentary section of arailway-car, show in gin elevation a seat and my improved electricheater suspended therefrom. Fig. 2 is an end view of the seat andheater. Fig. 3 is an elevation of the heater shown in Fig. 1 on a largerscale and showing it partly dissected away or in section to clearly showits construction. Fig. 4 is a transverse section of Fig. 3. Figs. 5 and6 are fragmentary elevations of the resistant-helix and itssupporting-rod. Figs. 7 and 8 are respectively similar views showinganother variation in construction. Fig. 9 is an elevation, partlydissected or broken away in vertical mid-section, showing the preferredconstruction of my invention. Fig. l0 is a fragmentary longitudinalsection of a modified construction. mentary plan of a dat coil-heater.

In this specification the word helix is used in the sense of a linewound progressively around a cylinder after the manner ofthe thread of ascrew. The word spiral is used in its generic sense to include either ahelix or a iiat spiral, by which I mean a line winding about any oneplane and continually receding from the center.

In all the. ligures let A designate a helix of resistant-wire, and let Bdesignate a rod or wire support therefor.

My present invention is characterized by the combination, with a helix Aof resistantwire, of a supporting rod or wire B, which is Fig. ll is afraz,-l

extended parallel with and within the helix A in such manner as to forma continuous support for it by making tangential contact with itssuccessive convolutions. The supportingrod is of relatively smalldiameter, so that its tangential contact with the successiveconvolutions is of very minute area, so that practically the entiresurface of the resistant-wireforming the helix A is left free fromcontact with any supporting part and is surrounded by air or otherfluid, which can rapidly conduct off from it the heat which itgenerates. The supporting-rod is also made much smaller than theinternal diameter of the helix, so that it does not lill the latter, nordoes it to any material extent obstruct its interior, but leaves it openand free for circulation of air Within it. 4

In its simplest or elemental form my invention comprises merely asupporting rod or wire B, with an open helix A, of resistant-wire,passed over it, as shown in Fig. 6. The supporting-rod B may bestraight, as shown at the right in that figure; but ordinarily it is.desirable to concentrate a considerable length open to some degree ofobjection because of i the loose mounting of the resistant-helix. Inorder to prevent looseness or rattling of the helix upon -itssupporting-rod and to give it firm support thereon, the supporting-rodis bent or curved (most conveniently into a helix, as shown) and theresistant-helix is wound `and confined thereon under tension, eitherexpansive, as shown in Figs. 3, 4, and 5, in Figs. 9 and lO, and in Fig.ll, or contractile, as shown in Figs. 7 and 8, so that in either casefirm tangential contact is maintained with one side of thesupporting-rod. It is necessary to insulate the resistant-wire A fromthe supporting-rod B, and this may be done by coating either or bothwith anysuii IOO able heat-resistant insulation, preferably enamel.. Insome cases it may be preferable to coat the resistant-wire A with s uchenamel; but ordinarily (and in any case where air is the fluid to beheated) this is undesirable, because it impedes the escape of heat fromthe wire, so that it is preferable to enamel the supporting-rod B. Theenamel coating thereof is indicated in the drawings at a a. The word rodas used herein includes not merely a metal rod, but also any suitablesubstitute therefor, such as rods of glass or porcelain or any materialhaving sufiicient stiffness for the purpose and either an insulator initself or capable of being effectively coated with insulation.

The preferred form of my invention is that wherein the supporting-rod isbent into a helix, so that the resistant-helix A is itself formed into alarger helix. It has heretofore been proposed to make electric heatersby winding a resistant-wire into a continuous helix (which I will callthe minor helix) and then ceiling this helix helically into a larger ormajor helix, thus forming what I will call a compound7 helix. In thismanner a large amount of wire can be coiled in a comparatively smallspace without any portion of the wire touching at any point any otherportion or convolution thereof, and consequently this form of heater isadvantageous in that it forms a compact and concentrated heat-generator.One example of such a compound helix is that set forth in myapplication, Serial No. (M2950, filed August l2, 1897, (patented March8,1898, No. GOOAIZ) wherein the compound helix is supported exteriorlywithin a perforated tube.

I will now proceed to particularly describe the preferred constructionof my heater with reference to Figs. 3, A, and 9. The heaters shown inthese figures are for heating air, being adaptable to electric cars andto apartments, &c. The inclosing case of the heater has the general formof a horizontal cylinder, its opposite ends being formed by heads ordisks C C', between which is extended a foraminous or barred or gradedcasing D in the general form of an open-work tube. This casing may beformed of wires h b, coiled into a helix, as shown in Figs. 3 and 4, orpreferably it is made of perforated sheet metal, as shown in Fig. 9.Within the casing is centrally inclosed the resistant-helix A, supportedon its rod B, which is wound into a helix. In constructing the heaterproper, A B, the resistant-wire Ais first coiled on a mandrel in theusual way, and the supporting-rod B is coiled on a larger mandrel and,being` cut to the proper length, has its ends turned outward, so as topass through holes in the heads C C, after which the rod B is enameled.The helix A being then cut to the properlength is placed on the rod B bythreading the latter through it, after which the heater is put togetherby inserting one end of the rod A through a hole made for it in one ofthe heads, placing the outer casing D in position against this head, andthen applying the other head against the opposite end and inserting theother end of the rod through a corresponding hole therein. The heads areheld at fixed distances apart, which may be accomplished by providinglongitudinal tie rods or braces E E, as shown in Figs. 3 and 4, orpreferably by drawing the heads tightly against t-he opposite ends ofthe casing D, which is itself rigid, as shown in Fig. 9, this beingaccomplished by screwing nutsff upon the threaded ends of thesupporting-rod B in such manner as to stretch this rod, so that it ismade to serve both as a support for the resistant-helix and as a tie fordrawing together the opposite heads. In the construction shown in Figs.3 and et the tie-rods hold the heads rigidly apart, and being three innumber and arranged close against the coiled wires Z) t) of the casingthese wires are held properly in concentric position. In thisconstruction the helical supporting-rod B is also stretched or distendedby screwing the nut f upon one end thereof and screwing the base of abindingpost c'. upon its opposite end. Thus in either construction therod or helix B is distended, the amount of stretch thus imparted to itbeing sufficient to render it hrm and rigid, so that it shall forni astiff support for the resistant-helix. A similar result can be attainedby forcingits ends together, so as to put it under compressive stress;but a distensive stress is obviously preferable.

In the case of heaters of excessive length, or where the supporting-rodis not sufficiently stiff, tie-rods E E may be arranged to directlysupport the supporting-rod B, as shown in Figs. 7 and 8, where also theheater is shown as devoid of any casing. Otherwise the con` structionshown in Figs. 7 and 8 dilfers from that shown in Figs. 3, 4, 5, (i, 9,and l0 only in that the helix A is wound under distensive tension, sothat it tends to contract upon the supporting-wire, whereas in Figs. 3,t, 9, and l() it is wound under compressive stress, so that it tends toexpand. To impart to the wire an expansive tendency, it is wound openlyupon a mandrel and is compressed upon the su pporting-helix, while togive it a contractile tendency it is wound closely upon the mandrel andit is stretched upon the supporting-wire.

Vith either of the constructions described all that is necessary tocomplete the electric heater is to make electrical-circuit connectionswith the opposite ends of the resistantwire. For this purposebinding-posts c c may be provided, as shown in Figs. l and 3, or thecircuit-wires may be connected directly with the nuts d d, which clampthe ends of the resistant-wire, as shown in Fig. 9. If it is desired tomake both electric connections at one end of the heater, thesupporting-rod B may readily be used as an electric conductor, as shownin Fig. 3, where the current is supposed to enter by binding-post c,which coniinunicates with one end of the wire helix A,

IOO

IIO

y the helix and conducts away the heat With the other end of whichpasses through the opposite end and is electrically connected by aconducting strip or yoke e to the end of the supporting-rod B, so thatthe current returns through this supporting-rod, the opposite end ofwhich is connected to the binding-post c.

For heating air my improved heater is arranged horizontally, and if anouter casing D is employed it is made with perforations or air-spaces ofample area for admitting a large flow of air through the heater toconduct away the heat given out by the resistant-helix A. The heater isextended horizontally-- that is to say, the axis around which themajorhelixis wound is a horizontal aXis-so that by reason of the maj orconvolutions being arranged somewhat close together practically all theair ascending through the heater is'forced to flow through the compoundhelix, so that the air is repeatedly cut up or subdivided by the hotwires, and thereby is most eifectively heated. In my heater theresistant-helix is wound upon a skeleton support which does not opposethe circulation of air, and consequently the air has access to allportions of apparently equal effectiveness from all portions, so thatthe entire length of resistant- Wire remains to all appearance ofuniform temperature. In this respect my heater is an importantimprovement over those heaters having a compound helix supported bybeing wound about a solid spirally-grooved cylinder, in which not onlyis a large proportion of each convolution on its inner side in contactwith the grooves of the cylinder, but the latter obstructs thecirculation of air, so that the portions of the helix lying on top ofthe cylinder are not reffectively cooled and become overheated, and asthe helix is necessarily wound in tension on the cylinder the overheatedportions yield and permit the convolutions elsewhere to draw closertogether, thereby occasioning frequent short-circuitin g of the convolutions on the lower sides by their mutual contact. These difficulties arewholl y overcome in my heater.

My improved heater is also an important improvement over a constructionthat has been proposed wherein the resistant-wire is Wound into a helixtightly around a supporting-core of enameled rod which extends helicallyabout a vertical axis. That const-ruction loses the advantage of an openhelix since the core fills the minor helix so that air cannot circulateWithin its convolutionsm'hile the vertical arrangement provides acentral axial that by passing a current through the heater the water maybe heated in transit. Such a pipe is shown in Fig. 10 at F. This pipeshould either be of insulating material, as in the case of a rubberhose, or else its inner surface should be coated with insulatingmaterial, as shown atj. Thus an iron pipe internally enameled orglass-coated may be employed. This interior insulation for the pipe may,however, be dispensed With in case the resistant-coil A is of enameledwire or is otherwise insulated. If the compound helix is of theconstruction shown in Fig. 10, where the helix A tends to'expand uponthe rod B, it may be made a close lit with the tube in which it is to bedrawn, s0 that it will yieldingly hold itself concentrically therein bymeans of the elasticity of the Wire A. This will in the case of afiexible hose permit of the slight distortion thereof out of a truecircle, which is apt to occur when it is'iiexed.

My invention is not to be understood as limited to a heater in which theresistant-Wire is formed into a compound helix, as the helix A, ofresistant-wire, maybe arranged in other shapes, according to the purposefor which the heater is to be applied. Thus for va fiat heater adaptedfor cooking it may be desirable to carry the helix A around in a flatspiral, as shown in Fig. 11. In such case the supporting-wire B shouldbe carried inside the helix A.

An important advantage of my invention is that the resistant-helix bysurrounding the supporting-rod is held thereon with such certainty as toprevent all displacement or escape, so that it is impossible for one ofthe major convolutions to be displaced into .contact with another, andalso in the event of breakage of the resistant-wire the severed ends areconfined and the helix cannot unwind or escape from its support;

Although it is within my invention to use a plurality of supporting-rodsB within the resistant-helix instead of one, and my claims herein aredesigned to include such a modification of my invention, yet I do notherein claim such construction specifically, having claimed the same inmy divisional application, Serial No. 701,493, led January 7,1899.

I claim as my invention the-followiugd`e fined novel features,substantially as hereinbefore specified, namely:

1. An electric heater comprising an open helix of resistant-wire havingsu lficient stiffness or resilience to retain its helical form, and asupport therefor consisting solely of a rod or stiff wire extendedwithin said helix, of materially smaller diameter than the interiorthereof, so that the helix is interiorly open for free circulation ofair within it, and

IOO

IIO

supporting the convolutions of said helix by tangential contacttherewith at single points only of their circumference.

2. An electric heater comprising an open helix of resistant-wire havingsufficient stiffness or resilience to retain its helical form,

and a support therefor consisting solely of a rod or sti wire extendedwithin said helix, of materially smaller diameter than the interiorthereof, so that the helix is interiorly open for free circulation ofair within it, and supporting the convolutions of said helix bytangential contact therewith, at single points only of theircircumference, and said helix confined on said support under stress insuch manner that its convolutions are pressed elastically into suchtangential contact therewith.

3. An electric heater comprising a helix of resilient resistant-wire anda support therefor, said support consisting solely of a rod or stiffwire extended within the helix and of materially smaller diameter thanthe interior thereof so that the interior of the resistant-helix is openfor circulation ot air Within it, and the supporting-rod curved, and thehelix confined thereon so that it passes elastically into tangentialcontact with said supporting-rod.

4. An electric heater comprising a resilient helix of resistant-wirecombined with a support therefor of helical insulating-rod extendedwithin said helix,of materially smaller diameter than the interiorthereof and maliing only tangential contact with it.

5. An electric heater comprising a helix of resistant-wire and a supporttherefor, consisting of a rod extended within said helix, of materiallysmaller diameter than the interior thereof, so that it touches ittangentially only, said helix and supporting-rod being coiled spirally,and the resistant-helix being confined under stress so that it presseselastically into tangential contact with one side of saidsupporting-rod.

6. An electric heater comprising a helix of resistant-wire and a supporttherefor, consisting of a rod extended within said helix, and ofmaterially smaller diameter than the interior thereof, so that ittouches it tangentially only, said helix and supporting-rod being coiledspirally, and the resistant-helix being confined under compressivestress so that it tends to expand into a larger spiral and pressesoutwardly into tangential contact with the inner side of saidsupporting-rod.

' 7. An electric heater comprising a minor helix of resistant-wirecoiled spirally into a major helix, and a helicalsupporting-rod extendedwithin said minor helix, and of materially smaller diameter than theinterior thereof, so that it touches it tangentially only, the interiorof the resistant-helix being open for circulation of air within it.

S. An electric heater' coinprisinga helix of resistant-wire coiledspirally into a major helix, around a horizontal axis, with its majorconvolutions closely adjacent but out of contact, and a helicalsupporting-rod extended parallel with said major helix and within and intangential contact with the convolutions of the minor helix, theinterior of the latter and of the major helix being open for circulationof air,whereby air circulating upwardly through said resistant compoundhelix, is thoroughly subdivided by the convolutions of resistantwire,and thereby effectively heated.

i). An electric heater comprisin ga minor hclix of resistant-wire coiledinto a major helix, combined with a supporting-rod coiled helically andextended within said minor helix, and the latter confined under stressso that it presses elastically into tangential contact with one side ofsaid supporting-rodl0. An electric heater comprising a helix ofresistant-wire coiled into a major helix, combined with a supporting-rodcoiled helically and extended within said resistant-helix, and thelatter having an expansive tendency, whereby its convolutions bearoutwardly against the inner side of said supporting-rod.

ll. An electric heater comprising a helical supporting-rod, an openhelix of resistantwire wound spirally into a major helix, said rodextendedY within said open helix and of materially smaller diameter thanthe interior thereof, so that the latter is supported by tangentialcontact with said rod, combined with opposite end heads, to which theends of said supporting-rod are fixed, and a rigid connection betweensaid heads.

l2. An electric heater comprising a helical supporting-rod, an openhelix of resistantwire wound spiraliy into a major helix, said rodextended within said open helix and of materially smaller diameter thanthe interior thereof, so that the latter is supported by tangentialcontact with said rod, combined with opposite end heads, to which theends of said supporting-rod are fixed,and an open-work or foraminouscasing extending between said heads and inclosing said resistant-helix.

13. An electric heater comprising a helical supporting-rod B and aresilient helix A supported thereon, combined with opposite end headsrigidly connected together so that they are held at a iixed distanceapart, and the ends of said supporting-helix connected to said heads anddrawn apart to put the helix under tension and thereby render it rigid.

let. An electric heater comprising a helical supporting-rod B and aresilient helix A snpported thereon, combined with opposite end headsand an open-work tubular casing supported between them, inclosing saidhelices, and serving as a rigid connection to hold the heads apart, andthe ends of said helix B connected with the respective heads, with ascrewthread connection for drawing the supporting-helix and hea-dtogether, whereby the supporting-helix is distended between the headsand made rigid, and the heads are held together against the casing.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

EDWARD E. GOLD.

'Vitn esscs:

ARTHUR C. FRAsnn, GEORGE H. FRASER.

IOS

IIO

